Quenching-induced atom-stepped bimetallic sulfide heterointerface catalysts for industrial hydrogen generation

Developing non-noble metal hydrogen evolution reaction (HER) electrocatalysts with high activity and durability at ampere-level current densities is vital for emerging anion exchange membrane (AEM) water electrolysis , but it remains challenging. Here we present an atom-stepped nickel–cobalt bimetallic sulfide (AS-Ni 3 S 2 /Co 3 S 4 ) heterostructure that exhibits superior HER performance, with ultra-low overpotentials of 28 and 195 ​mV at current densities of 10 and 2000 ​mA ​cm −2 , respectively. Experimental analyses and theoretical calculations revealed that the work-function-induced interfacial built-in electric field drives electron transfer from Ni 3 S 2 to Co 3 S 4 via Ni–S–Co interfacial bridging, which effectively accelerates water activation and optimizes hydrogen adsorption and desorption . An AEM electrolyzer using an AS-Ni 3 S 2 /Co 3 S 4 heterostructure as the cathode required cell voltages of only 1.71 and 1.79 ​V to reach 1.0 and 2.0 ​A ​cm −2 , respectively, and operated stably for 1200 ​h without activity degradation.